Research & Development in Sand Texture Sedimentology
Updated 21-Nov-09 05:26h
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Major scientific results ( J. BREZINA, 1989: see References, item 60):
1 |
Mathematical formula for the drag
coefficient as a function of the Reynolds' number and shape factor of sedimenting
particles. The formula makes it possible to mutually compute grain size, grain shape, grain density, and sedimentation velocity (J. BREZINA, 1979: ref. 52, pdf file to view & download). In contrast to the popular formulas by Matthews (R. J. GIBBS et al., 1971: ref. 64), the relationship by Brezina features a full polynomial solution (free of the limitations known for the Gibbs formulas), not only for spherical but also irregular natural grains, and is valid within a wide range of Reynolds' numbers (it covers both the Stokes' and Newton's laws). Our program SedVar performs the conversions both for single numbers and for distributions (from a PSI-sedimentation velocity distribution). |
2 |
Mathematical expression for limiting terms of
mutual hydrodynamic interference of sand-sized grains sedimenting in a stratified
suspension (J. BREZINA, 1972b: ref. 45). This relationship determines a suitable size of a sand sample at which the grains sediment without observable streaming. |
3 |
Transformation of dispersity variables (units)
(concept introduced in J. BREZINA, 1963c: ref. 33), may
suppress non-normal (non-Gaussian) features of certain statistical distributions. For example, the negative skewness of a PHI grain size distribution can be reduced or removed by its transformation into the distribution of PSI settling rate or log Re (Reynolds' number). Note that in this paper dated 1963, the author used the Russian experimental data by A. A. SARKISIAN, 1958, the only data available to him at that time. Later, living already in a free world, the reliable results from American studies (particularly those by B. C. COLBY, and R. P. CHRISTENSEN, 1957, E. F. SCHULZ, R. H. WILDE + M. L. ALBERTSON, 1954) provided the author a solid base for his drag coefficient formula, and the resulting particle size (specified by shape factor) and sedimentation velocity relationships (J. BREZINA, 1979: ref. 53). |
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